Polyurethane injected boot assembly and associated manufacturing method

ABSTRACT

A footwear assembly having an upper that comprises a neoprene sock with a foot portion integrally connected to a leg portion. The foot portion has heel, vamp and under-foot portions. The leg portion has front shin, side wall, and rear calf-side portions. The upper has a unitary, outer, injection molded layer molded directly onto the foot and shin portions of the neoprene sock, while the sidewall and rear calf-side portions remain substantially uncovered by the injection molded layer. The injection molded layer encases the foot portion of the neoprene sock. The injection molded layer on the shin portion defines a shin guard portion having a necked down area integrally connected to the injection molded layer at the vamp portion, wherein the shin guard extends upwardly from the necked-down portion in an outwardly diverging shape away from the vamp.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.16/438,392, filed Jun. 11, 2019, which is a continuation of U.S.application Ser. No. 15/482,496, filed Apr. 7, 2017 (U.S. Pat. No.10,327,501), which is a continuation of U.S. application Ser. No.14/931,785, filed Nov. 3, 2015 (U.S. Pat. No. 9,642,416), which is acontinuation of U.S. application Ser. No. 13/873,105, filed Apr. 29,2013 (U.S. Pat. No. 9,204,685), which is a continuation of U.S.application Ser. No. 13/685,619, filed Nov. 26, 2012 (U.S. Pat. No.8,984,776), which claims priority to and the benefit of U.S. ProvisionalPatent Application No. 61/565,359, titled “Polyurethane Injected BootAssembly and Associated Manufacturing Method,” filed Nov. 30, 2011, allof which are incorporated herein in their entirety by reference thereto.

TECHNICAL FIELD

Embodiments of the present invention are directed to waterprooffootwear, such as neoprene-based boots, and associated manufacturingmethods.

BACKGROUND

Waterproof footwear, such as boots, are used in outdoor recreationalactivities as well as in a number of industrial and professional uses.For example, waterproof boots are often used in hunting and fishing toensure that the sportsman's feet remain dry during the recreationalactivity. Additionally, waterproof boots are used in the animalhusbandry and farming environments, as well as many other professionalenvironments.

One type of waterproof boots includes over-the-calf boots made entirelyof rubber. Other conventional waterproof boots include an outer rubberwaterproof layer over an inner layer of supporting material. The use ofrubber as the waterproof material can provide a number of functionalbenefits, because rubber of sufficient thickness is strong, resilient,puncture resistant, and fairly durable. Such rubber boots, however, aretypically inflexible, heavy, and do not fit the wearer's foot and/or legvery well.

Other waterproof boots have been developed that include a neoprene innerlayer fully covered by an outer layer of rubber vulcanized onto theneoprene. This neoprene and vulcanized rubber construction provides alight weight boot that fits better and is more comfortable than theall-rubber boots. The manufacturing process of laying up the rubber andvulcanizing it onto the outside of the neoprene sock is a fairlylaborious manufacturing process, which can increase the boot'smanufacturing cost. The heat applied to the boot assembly during thevulcanization process can also have a negative effect on the innerneoprene sock. For example, the neoprene may be susceptible to taking aset and losing elasticity during the vulcanization process. Accordingly,there is a need for an improved light weight, waterproof boot andassociated method of manufacture.

SUMMARY

Boot assemblies and associated manufacturing methods in accordance withthe present disclosure provide waterproof boots that overcome drawbacksof the prior art and that provide other benefits. In at least oneembodiment, a boot assembly includes a neoprene sock having inner andouter surfaces, and an outer layer of injection molded material onselected portions of the neoprene sock's outer surface including on theheel area, the ankle area, the vamp area, the under-foot area, and theshin area. Other portions of the neoprene sock's outer surface remainuncovered by the injection molded material.

An aspect of the present disclosure provides a footwear assembly havingan outsole and an upper connected to the outsole. The upper comprising asock layer having a leg portion and a foot portion integrally connectedto the leg portion. The leg portion has a front shin portion, side wallportions and a rear calf-side portion. The foot portion has a vampportion; and a unitary outer injection molded layer molded directly ontoat least a portion of the sock layer. The unitary outer injection moldedlayer comprises a first injection molded region that encases the footportion of the sock layer. The injection molded layer has a secondinjection molded region on the shin portion of the leg portion of thesock layer, wherein the sidewall portions and calf-side portion of thesock layer remain exposed and substantially uncovered by the secondinjection molded layer, and wherein the second injection molded layerincludes a shin guard having a necked down area and a shin area that iswider than the necked down area, the necked down area interconnectingthe shin area and the vamp portion.

Another aspect of the present disclosure provides a lightweight,waterproof footwear assembly combineable with an outsole. The assemblycomprises: an upper connectable to the outsole, and the upper has a sockincluding a foot portion and a leg portion integrally connected to thefoot portion. The leg portion has a front shin portion, side wallportions and a rear calf-side portion. The upper has a unitary outerinjection molded layer molded directly onto the foot portion of the sockand a first portion of the leg portion of the sock while second portionsof the leg portion remain exposed and substantially uncovered by theouter injection molded layer. The injection molded layer encases thefoot portion of the sock. The injection molded layer at the foot portionhas a plurality of integral convertible channels of reduced thicknessaround the foot portion in a configuration conforming to a top edge of aboot, wherein the convertible channels define cut lines along which theupper can be cut during manufacture to define a top edge of a boot of aselected height.

Another aspect of the present disclosure provides a lightweight,waterproof footwear assembly, comprising an upper connected to anoutsole. The upper has a sock that has a foot portion with an ankleportion, a heel portion, a vamp portion, and an under-foot portion. Thesock has a leg portion integrally connected to the foot portion, and theleg portion has a front shin portion, side wall portions and a rearcalf-side portion. A unitary outer injection molded layer is moldeddirectly onto the foot portion of the sock and a first portion of theleg portion of the sock while second portions of the leg portion remainexposed and substantially uncovered by the injection molded layer. Theinjection molded layer encases the foot portion of the sock and definesa shin guard integrally connected to the injection molded layer of thefoot portion.

Another aspect of the present disclosure provides a footwear assemblyhaving an outsole and an upper connected to the outsole. The uppercomprises a neoprene sock having foot and leg portions, and the footportion is integrally connected to the leg portion. The foot portion hasa heel portion, a vamp portion and an under-foot portion. The legportion has a front shin portion, side wall portions, and a rearcalf-side portion. The upper has a unitary outer injection molded layermolded directly onto the foot portion and the shin portion of theneoprene sock, while the sidewall portions and rear calf-side portionremain exposed and substantially uncovered by the injection moldedlayer. The injection molded layer encases the foot portion of theneoprene sock. The injection molded layer on the shin portion defines ashin guard portion having a necked down area integrally connected to theinjection molded layer at the vamp portion, wherein the shin guardextends upwardly from the necked-down portion in an outwardly divergingshape away from the vamp.

Another aspect of the disclosure provides a lightweight, waterprooffootwear assembly combineable with an outsole. The footwear assembly hasan upper connectable to the outsole, and the upper comprises a neoprenesock having a foot portion integrally connected to a leg portion. Thefoot portion has an ankle portion, a heel portion, a vamp portion, andan under-foot portion. The leg portion has a front shin portion, sidewall portions and a rear calf-side portion. The upper comprises aunitary outer injection molded layer molded directly onto the footportion and a first portion of the leg portion of the neoprene sockwhile second portions of the leg portion remain exposed andsubstantially uncovered by the injection molded layer. The injectionmolded layer encases the foot portion of the neoprene sock. Theinjection molded layer at the foot portion has a plurality of integralconvertible channels of reduced thickness around the ankle portion in aconfiguration conforming to a top edge of a boot. The convertiblechannels define cut lines along which the upper can be cut duringmanufacture to define a top edge of a boot of a selected height.

Another aspect of the disclosure provides a method of making awaterproof footwear assembly. The method comprises enclosing a neoprenesock in an injection molding assembly, wherein the neoprene sockcomprises an interior area and an exterior surface facing away from theinterior area. The neoprene sock has a foot portion integrally connectedto a leg portion. The foot portion has a heel portion, a vamp portionand an under-foot portion. The leg portion has a front shin portion,side wall portions and a rear calf-side portion. The method includesinjecting a flowable, injection moldable material into the moldingassembly adjacent to the foot portion of the neoprene sock. The methodincludes forming an injection molded layer of the injection moldablematerial directly on a portion of the exterior surface of the neoprenesock, wherein the injection molded layer covers the foot portion and thefront shin portion, and wherein the sidewall portions and the rearcalf-side portion remain exposed and substantially uncovered by theinjection molded layer. The method includes molding the injectionmoldable material onto a portion of an outsole connecting the outsole tothe neoprene sock, wherein an under-foot portion of the injectionmoldable material interconnects the neoprene sock to the outsole.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view of a waterproof boot assembly in accordancewith an embodiment of the present disclosure.

FIG. 2 is a side elevation photograph of an alternate embodiment of theboot assembly of FIG. 1.

FIG. 3 is a side elevation view of the boot assembly of FIG. 1.

FIG. 4 is a cross-sectional view taken substantially along line 4-4 ofFIG. 1.

FIG. 5 is a cross-sectional view taken substantially along line 5-5 ofFIG. 3.

FIGS. 6-8 are side elevation views of alternate embodiments of the bootassembly of FIG. 1.

FIG. 9 is an isometric view of a mold assembly used in manufacturing theboot assembly of FIG. 1; the mold assembly is shown in an open position.

FIG. 10 is an isometric view of the mold assembly of FIG. 9 shown in apartially closed position.

DETAILED DESCRIPTION

The present disclosure describes waterproof boot assemblies and methodsof manufacturing the boot assemblies in accordance with certainembodiments of the present invention. Several specific details of theinvention are set forth in the following description and the Figures toprovide a thorough understanding of certain embodiments of theinvention. One skilled in the art, however, will understand that thepresent invention may have additional embodiments, and that otherembodiments of the invention may be practiced without several of thespecific features described below.

As seen in FIGS. 1-3, a waterproof boot assembly 10 in accordance withan embodiment of the present disclosure includes an upper 12 integrallyconnected to an outsole 14. The upper 12 is an over-the-calf upper thatincludes a leg portion 16 with an ankle portion 17 integrally connectedto a foot portion 18, which has a heel portion 20 and a vamp portion 22.The upper 12 includes a full-foot neoprene sock 24 shaped and sized toreceive the wearer's foot and to extend upwardly over the ankle andcover the wearer's shin and calf. The neoprene sock 24 has an innerlayer 26, an outer layer 28, and a neoprene layer 30 sandwiched betweenthe inner layer 26 and the outer layer 28. The inner layer 26 definesthe interior area of the entire boot from the foot portion 18, throughthe ankle portion 17 and to the top of the leg portion 16. The innerlayer 26 can be a fabric material, such as nylon, cotton, canvas,fleece, insulation, wool, mesh, or other selected materials.

The neoprene layer 30 carries the inner layer 26 and the outer layer 28.The neoprene layer of the illustrated embodiment has a thickness ofapproximately 3.5 mm. Other embodiments can include a neoprene layerwith a thickness of approximately 7.0 mm. Yet other embodiments caninclude a neoprene layer with other thicknesses or a combination ofthicknesses. The neoprene layer 30 of the illustrated embodiment isformed from two pieces of neoprene material. One piece forms the floorregion upon which a wearer's foot is supported, and the second piece ofneoprene is shaped to cover the vamp, heel, ankle and lower leg regions.The two pieces of neoprene can be connected to each other via stitchingor other conventional techniques for joining pieces of neoprenetogether. In one embodiment, the floor region of the neoprene sock 24 isformed by a puncture resistance insole board, such as a LENZI® insoleboard or the like, to which the rest of the neoprene layer 30 isattached and/or stitched. In the illustrated embodiment, the secondpiece of the neoprene is stitched to itself to close the heel, ankle,and leg portions of the neoprene sock 24. In this arrangement, theneoprene sock 24 has a stitched seam 32 that extends vertically alongthe back side of upper (i.e., along the calf-side 34 of the leg portion16) between the heel portion 20 and the top of the leg portion 16. Otherembodiments can have a seam in other locations, such as along the top ofthe vamp portion 22 and along the front or shin-side 36 of the legportion 16. In yet other embodiments, other configurations of theneoprene can be used to provide a seam in other locations.

The outer layer 28 can also be a fabric material securely affixed to theouter surface of the neoprene layer 30. The outer layer 28 can cover theentire neoprene layer. In other embodiments, the outer layer 28 cancover only selected portions of the neoprene layer, such as thoseportions of the neoprene sock 24 exposed and visible from exterior ofthe boot assembly 10, as discussed in greater detail below. The outerlayer 28 can be a durable fabric material, such as Spandura®, nylon,cotton, canvas, fleece, wool, mesh, or other selected materials. Theouter layer can also be one or more selected colors, and/or it caninclude camouflage, designs, images, indicia, or other visual features.

The upper 12 includes an outer polyurethane (PU) layer 40injection-molded directly onto portions of the neoprene sock 24, whileother portions of the neoprene sock remain uncovered (i.e., PU-free).The PU material can be injection molded directly onto the outer surfaceof the neoprene layer 30, or onto the outer surface of the outer layer28, or both. The PU material is lightweight, durable, and has betterinsulative properties than vulcanized rubber. The injection-molded PUlayer 40 is also permanently connected to the outsole 14 so as tofixedly connect the outsole 14 to the upper 12. In the illustratedembodiment, the injection-molded PU layer 40 fully covers the neoprenesock 24 in the vamp portion 22, the heel portion, 18 and the ankleportion 17. Other portions of the neoprene sock 24, such as thecalf-side 34 and sidewalls of the leg portion 16, remain uncovered andexposed.

As shown in FIGS. 4 and 5, the injection-molded PU material is moldedaround the entire foot portion of the neoprene sock 24, such that the PUmaterial extends under the bottom of the neoprene sock between thesock's bottom panel 25 and the outsole 14. This “under-foot” layer of PUmaterial between the neoprene sock 24 and the outsole 14 is sufficientlythick to define a cushioning and/or shock attenuation layer under thewearer's foot, so as to effectively act as an integrated midsole portion29 to which the outsole 14 is attached. The integrated PU midsoleportion 29 can have varying thicknesses under the foot to achieveselected performance or comfort objectives. In one embodiment, theintegrated PU midsole portion 29 can be thicker in the heel area toabsorb or otherwise reduce impact loads at heel strike of the wearer'sgait cycle. The integrated PU midsole portion 29 can be configured inthe arch area to essentially encapsulate a shank positioned under theneoprene sock's bottom panel 25 in the arch area. In another embodiment,the shank can be positioned between the outsole 14 and the midsoleportion 29. In yet another embodiment can include the shank fullyencapsulated within the midsole portion 29. Accordingly, the injectionmolded PU material on the neoprene sock 24 can also include the integralmidsole portion underfoot, which is formed in the same single injectionmolding process, discussed in greater detail below.

The injection molded PU material can also be configured with a selectedthickness over the vamp portion 22 to provide impact protection to theinstep and/or metatarsal regions of the wearer's foot. In oneembodiment, each of the neoprene layer and the PU material havecushioning and shock attenuation characteristics. The combination of theneoprene layer and the PU material layer at the vamp portion 22 can beconfigured with a selected thickness to form an integrated metatarsalguard construction that provides sufficient shock absorption and impactabatement to meet or exceed the ANSI and/or ASTM metatarsal guardrequirements for footwear. Accordingly, the resulting footwear assembly10 can be a certified metatarsal guard footwear assembly. In oneembodiment, such metatarsal guard protection can be provided using aneoprene sock with a thickness of approximately 3.5 mm and the PUmaterial having a thickness of approximately 4 mm-8 mm at least at thevamp portion. In one embodiment, the PU material has a thickness ofapproximately 6 mm at the vamp portion and/or the shin guard portion.Other embodiments can use other thicknesses of the neoprene sock and/orthe PU material to provide the selected metatarsal guard construction.

In another embodiment, a metatarsal guard insert 55 can be provided overthe vamp portion 22 of the neoprene sock prior to injection molding thePU material onto the neoprene sock 24. When the PU material is injectionmolded onto the neoprene sock 24, the metatarsal guard insert 55 isfully covered and/or encapsulated within the PU material. In thisconstruction, the metatarsal guard insert 55 may or may not be visiblefrom the exterior of the footwear assembly 10.

A similar construction may be provided with a toe guard insert 57covered by the PU material. A toe guard insert 57, such as a certifiednon-metallic toe cap, can be positioned over the toe area of theneoprene sock 24 prior to injecting the PU material onto the neoprenesock 24. When the PU material is injected onto the neoprene sock 24, thetoe guard insert 57 is fully covered and/or encapsulated by the PUmaterial layer. The result is a lightweight, highly insulative, boot orshoe having the certified toe guard protection.

In yet another embodiment, a puncture resistant layer 59 can be providedalong the bottom of the neoprene sock (i.e., under foot). The punctureresistant layer 59 can be a metallic or nonmetallic material thatprovides sufficient puncture resistance in accordance with the ANSI orASTM standards or other similar performance standard for footwear. Atleast one embodiment includes a puncture resistant material manufacturedby LENZI®. The puncture resistant material can be part of an insoleboard. The puncture resistant layer 59 can be positioned adjacent to thebottom of the neoprene sock 24, and then the PU material is injectionmolded onto the neoprene sock, so the puncture resistant material isfully covered and/or encapsulated by the PU material. The result is alightweight, durable, certifiable puncture-resistant footwear assemblythat meets or exceeds manufacturing, performance and safety requirementsand regulations for footwear.

The PU layer 40 also forms a shin guard 42 on the shin side 36 of theleg portion 16. The shin guard 42 has a narrow or necked-down area 44integrally connected to the PU material on the front of the ankleportion 17 above the vamp portion 22. The shin guard 42 extends upwardlyfrom the necked-down area 44 in an outwardly diverging shape to the topedge of the leg portion 16. The integral shin guard 42 terminates alongside edge portions 46 so that the front of the upper 12 protects thewearer's shin, while the sides of upper 12 are PU-free with the neoprenesock 24 uncovered and exposed. The necked-down portion 44 at the bottomof the shin guard 42 helps maintain flexibility and comfort of theboot's leg portion 16, while providing a path through which the PUmaterial can flow from the vamp and ankle portions to the shin guardarea during the injection molding process, discussed in greater detailbelow. In one embodiment, the PU material is injected into the mold(discussed below) near the toe portion of the neoprene sock 24 so the PUmaterial substantially simultaneously flows around the foot portion ofthe neoprene sock and along the shin portion. In other embodiments, thePU material can be initially injected into the mold adjacent to adifferent portion of the neoprene sock during the molding process.

The embodiment(s) described herein and shown in the figures include thelayer of PU material injection molded onto the selected portions of theneoprene sock. Other embodiments can utilize other suitable flowable,injection moldable materials, such as thermoplastic polyurethane (TPU),Styrene Ethylbutylene Styrene (SEBS), or other suitable flowableinjection-moldable material that can be injection molded directly ontoselected portions of the neoprene sock 24 in a single molding process.

The injection molded layer 40 can be any of a range of colors orcombination of colors. The PU layer 40 in other embodiments can includea selected camouflage pattern. In yet other embodiments, theinjection-molded layer 40 other may be transparent or semi-transparent,so that portions of the neoprene sock 24 under the injection moldedlayer can be visible. As an example, one embodiment the neoprene sock 24includes a camouflage pattern over most of its outer surface, and theinjection molded layer is made of a clear TPU or clear SEBS material sovirtually all the camouflage pattern of the neoprene sock 24 is visibleto the user, including through the injection molded layer.

In the illustrated embodiment, the leg portion 16 of the upper 12includes a gusset 48 on the calf-side 34 of the leg portion. The rest ofthe neoprene sock 24 above the ankle portion 17 on the calf-side 34 isexposed and not covered by the injection-molded PU material. The gusset48 can be formed of a neoprene material, rubber, or other suitableflexible material to accommodate the stresses and folding forces appliedto the gusset. The edges of the gusset 48 can be stitched directly tothe top area of the leg portion, thereby creating a one or more seamsbetween the gusset and the upper's leg portion. The seam(s) 32 along thecalf-side 34 of the leg portion 16 can be sealed by a strip ofvulcanized rubber, waterproof tape or other suitable waterproofcovering. In another embodiment, a flowable sealant, such as a flowablerubber, can be applied to the seam and allowed to dry or cure to providea waterproof covering over the seam(s). In another embodiment, a stripof PU material can be injection molded directly onto to neoprene sock 24during the single-shot injection-molding process so as to cover andwaterproof the entire seam 32. This seam-covering strip of PU materialis integrally connected to the injection-molded PU material of the ankleportion 17 above the heel portion 20. While the illustrated embodimentincludes the gusset 48, the upper 12 in other embodiments does notinclude a gusset 48. In such a configuration, the seam-covering strip ofPU material can extend all the way to the top edge of the upper. Inother embodiments, the leg portion 16 can include a zipper or otherexpandable/closeable entry system at the top of the leg portion that canhelp facilitate taking the boot assembly on and off of the wearer'sfoot/leg. Such entry system can be gusseted systems or gusset-freesystems.

As seen in FIGS. 1-4, the injection molded PU layer 40 has a pluralityof channels 50 formed into the PU material. The channels 50 are providedin the vamp portion 22, the ankle portion 17, the heel portion 20, andthe shin guard 42. These channels 50 define areas of the PU materialhaving reduced thicknesses, which decreases the overall weight of theboot assembly. In one embodiment, the PU layer at the channels has athickness of approximately 2 mm, and the thickness of approximately 4 mmaway from the channels 50. Other embodiments can have injection-moldedPU material with different thicknesses. The channels 50 can also defineflex grooves 51 in portions of the upper 12 that allow the upper 12 tobend or flex during use. For example, the flex grooves 51 in the vampportion 22 and in the front of the ankle portion 17 allow the upper 12to flex easily to accommodate for the movement of the wearer's lowerleg, ankle, and foot while walking or running.

The boot assembly 10 of the illustrated embodiment is a full,over-the-calf boot having a height of, as an example, sixteen oreighteen inches from the bottom of the outsole 14 to the top edge 53 ofthe leg portion 16. The boot assembly 10 is configured as a convertibleboot assembly that can be finished during the manufacturing process aseither the full over-the-calf boot or as a shorter boot/shoe. Theinjection-molded PU layer 40 is formed over the neoprene sock 24 with aplurality of the channels 50 being convertible channels 52 extendingaround the upper 12. The convertible channels 52 define areas alongwhich the upper 12 can be cut to shorten the upper and then finishedduring the manufacturing process to form shorter footwear. For example,FIGS. 3 and 6 show the convertible channels 52 that include a lowerconvertible channel 54 formed in the PU layer 40 around the upper 12just below the ankle portion 17. After the PU layer 40 is injectionmolded onto the neoprene sock 24, the upper 12 can be cut along thelower convertible channel 54 and the top edge of the upper is finished,such as with a binding stitch, to form a 4.5-inch slip-on waterproofshoe (FIG. 6), referred to as a “camp moc.”

FIGS. 3 and 7 show the convertible channels 52 that include a 7-inchconvertible channel 56 formed in the PU layer 40 around the upper 12just below the shin guard 42 (FIG. 3) and along the top edge of the restof the injection molded PU layer 24. The upper 12 can be cut along the7-inch convertible channel 56 and the top edge of the upper is finishedwith a binding stitch or the like to form a 7-inch slip-on waterproofboot (FIG. 7). FIGS. 3 and 8 show the convertible channels 52 thatinclude a 12-inch convertible channel 58 formed in the PU layer 40 inthe shin guard 42 between the necked portion 44 and the top edge 53 ofthe leg portion 16. The upper 12 can be cut along the 12-inchconvertible channel 58 and the top edge of the remaining upper 12 isfinished with a binding stitch or the like to form a 12-inch waterproofboot (FIG. 8). The 12-inch waterproof boot of the illustrated embodimentincludes portions of the neoprene sock 24 above the PU layer 40 thatremain exposed and uncovered by the PU material.

While the illustrated embodiments are shown with convertible channels 52that include at least the lower convertible channel 5.4-inch, the 7-inchconvertible channel 56, and the 12-inch convertible channel 58, the bootassembly 10 can include a greater or fewer number of convertiblechannels 52 in different positions and/or orientations along which theupper 12 can be cut and finished to form footwear of different heights.This configuration allows the same mold to be used in the manufacturingof a plurality of boot assemblies having different heights, which canincrease efficiency and reduce the manufacturing cost.

The boot assembly 10 of the illustrated embodiment is manufactured byforming the entire neoprene sock 24 having the selected inner layer 26and the outer layer 28. In the illustrated embodiment, the outer layer28 is a layer of Spandera™ that includes a camouflage pattern, but otherouter layers can be used. The neoprene sock 24 is securely positionedover a rigid last 60 of a mold assembly 62, shown in FIG. 9. The last 60is connected to and extends from a vertical support 64 in a cantileveredarrangement. The mold assembly 62 includes a pair of side die plates 66pivotally attached to the support 64. The side die plates 66 are movablefrom an open position (FIG. 9) and a closed position (FIG. 10). In theopen position, the side die plates 66 are spaced away from the last 60so as to expose and provide access to the last 60. In the closedposition, shown in FIG. 10, the side die plates 66 enclose the last 60and closely conform to the neoprene sock on the last.

The mold assembly 62 can be configured for use with neoprene sockshaving different thicknesses, such as for different models of the bootassembly. In one embodiment, the last 60 is sized and configured toreceive the thickest neoprene sock in the different models of the upper.When a thinner neoprene sock is needed for a different model, a spacercan be placed on the last to accommodate for the thickness variations ofthe neoprene material. As an example, the mold assembly 62 of oneembodiment is constructed for use with a neoprene sock 24 having athickness of about 7 mm. The last 60 for the mold assembly 62 is for apredetermined foot size, such as a size US9, using the 7 mm sock. Thesame mold assembly 62 is also used for a boot having a neoprene sockwith a 3.5 mm thickness, by inserting a 3.5 mm thick spacer (such as aspacer sock) on the last 60 before the 3.5 mm thick neoprene sock 24 isplaced on the last. Accordingly, the 3.5 mm neoprene sock is slippedonto the last 60 over the spacer sock. In one embodiment, the spacersock is a 3.5 mm thick neoprene spacer sock.

In this embodiment using the 3.5 mm thick neoprene sock over the last 60and the spacer sock, the resulting boot assembly 10 will have a largerinterior area than the boot with the 7 mm thick neoprene sock made usingthe same mold assembly 62. The mold assembly 62 is specificallydesigned, however, so that the boot with the 3.5 mm thick neoprene sockwill be a larger size (e.g., approximately size US10) than the boot withthe 3.5 mm thick neoprene sock (e.g., approximately size US9).Accordingly, the exact same mold assembly 62 can be used to make twodifferent versions of a boot with different neoprene thicknesses andwith different boot sizes. This decreases manufacturing costs by usingthe same mold assembly 62 during the injection molding of a plurality ofmodels or versions of the boot assemblies without having to change orrevise the mold, other than by using spacer socks or other spacerdevices. Other embodiments include a plurality of molds with lasts thatare specifically sized to accommodate neoprene socks having differentthicknesses with out needing to use a spacer or the like.

The mold assembly 62 also has an outsole die plate 68 configured tosecurely retain and position the outsole 14 (FIG. 3) immediatelyadjacent to the bottom of the neoprene sock 24 (FIG. 3). The outsole dieplate 68 of the illustrated embodiment is pivotally attached to the endportion of one of the side die plates 66. In one embodiment, the outsoledie plate 68 can be removeable from the side die plate 66 and replacedwith a different outsole die plate. This allows the mold assembly 62 tobe used with different outsoles or different outsole patterns ormaterials. For example, a run of boots with a first construction oroutsole pattern can be made using the mold assembly, and then outsoledie plate 68 can be quickly and easily removed and replaced with adifferent outsole die plate. The mold assembly 62 with the new outsoledie plate 68 can then be used to make another run of boots havingdifferent outsoles from those of the first run. In other embodiments,the outsole die plate 68 can be changed to modify the configuration(i.e., thickness, arrangement, distribution, etc.) of the integrated PUmidsole portion 29 without having to use a completely different mold.The removeable outsole die plates 68 can also be configured toaccommodated outsoles made of different materials. One outsole die plate68 can be used with rubber outsoles, and another outsole die plate canbe used for an injection molded outsole or an other type or style ofoutsole.

The outsole die plate 68 releasably locks onto the bottom of the otherside die plate 66 when in the closed position to fully enclose theoutsole 14 and the neoprene sock 24 within the mold assembly 62. Themold assembly 62 securely retains the neoprene sock 24 in a position sothat the PU material can be injected into the mold so as flow over andcover only the selected portions of the outsole and neoprene sock, whilethe remaining portions of these components remain free of the injectionmolded PU materials. The mold assembly 62 is also configured toprecisely hold the outsole 14 apart from the bottom panel of theneoprene sock 24 such that PU material will flow and fill the entirespace between the sock's bottom panel and the outsole 14 to securely fixthe outsole 14 to the upper 12. In at least one embodiment, the outsole14 may include an adhesive material that adheres the outsole 14 directlyto the bottom of the neoprene sock 24 as the PU material is injectedinto the mold and over the selected portions of the outsole 14 and theneoprene sock 24.

The side die plates 66 have contoured interior surfaces 70 thatcorrespond in negative relief to the shape and arrangement of the bootassembly 10. For example, the contoured interior surfaces 70 have vamp,heel, ankle, and shin guard portions spaced a selected distance from theouter surface of the neoprene sock 24 in the corresponding vamp, heel,ankle and shin guard areas. Accordingly, during the injection moldingprocess, the flowable PU material is injected into the mold assembly 62,when in the fully closed position, and uniformly flows over the selectedouter surfaces of the neoprene sock 24 into only the spaces between thedie plates 66 and the neoprene sock 24 to form the PU layer 24.

The contoured interior surfaces 70 of the side die plates 66 alsoinclude a plurality of ridges 72 in selected locations that define theflex grooves 51 and the convertible channels 52 in the PU layer 40during the injection molding process. The contoured interior surfaces 70also include one or more dam portions 74 that firmly and sealably engagethe neoprene sock along the edges of the area to which the PU is allowedto flow. The dam portions 74 prevent the flowing PU material frombleeding onto the outer surface of the neoprene sock 24 that is toremain exposed and PU-free. The dam portions 74 must be carefully sizedand controlled so as to press against the neoprene sock 24 firmly enoughto prevent leakage of the PU material but not enough to crush and damagethe neoprene material. In at least one embodiment, the dam portions 74are carefully shaped and sized as a function of the characteristics ofthe PU material (i.e., the viscosity, etc.) and the characteristics ofthe neoprene material (i.e., its crush resistance) to ensure propercontrol of the flowing PU material without damaging the neoprene sock.

The dam portions 74 of the side die plates 66 also define the shape ofthe shin guard 42 and the necked down portion 44 between the bottom ofthe shin guard and the ankle portion of the upper 12. The side dieplates 66 are configured at the shin guard area and the necked down areaso that the PU material injected into the bottom of the mold assembly62, when in the closed position, will smoothly and uniformly flow overthe foot and ankle areas of the neoprene sock 42, and through the neckeddown portion and fully fill the space in the mold that defines the shinguard area. This shin guard area is shaped, sized, and configured in thediverging arrangement so that the injected PU material will consistentlyfill the entire space to form the entire shin guard 42 to the top edgeof the neoprene sock without leaving any air holes, bubbles or otherareas of incomplete dispersal of the PU material. Accordingly, the moldassembly 62 is configured for uniform repeatability of forming the bootassembly 10.

In operation, the empty mold assembly 62 is moved to the open position,and the neoprene sock 24 is securely positioned onto the last 60. Anoutsole 14 is positioned on the outsole die plate 68, and the moldassembly is moved to the closed position with the outsole die plate 68and the side die plates 66 fully enclosing the neoprene sock. In thisarrangement, the outsole 14 is also held in firm engagement with thebottom of the neoprene sock to allow a layer of adhesive to permanentlyadhere the two components together.

The mold assembly 62 is then locked in the closed position, and aselected volume of heated, flowable PU material is injected into themold assembly at a selected rate so as to flow over and bond to only thedesired areas of the neoprene sock 24 to form the PU layer. The PUmaterial also flows around selected portions of the outsole 14 to helphold the outsole in place and to provide a smooth transition between theoutsole 14 and the upper 12. The dam portions 74 on the die platescompletely block the PU material from bleeding onto portion of theneoprene sock 24 that are to remain uncovered and exposed. The injectedPU material is allowed to cure and cool, and then the mold assembly 62is unlocked and moved to the open position to expose the boot assembly10 on the last 60. The boot assembly 10 can then be removed from thelast 60, and another neoprene sock 24 positioned on the last 60 inpreparation for forming another boot assembly 10. This configurationallows all of the PU material to be applied to the neoprene sock in asingle injection molding operation, which can greatly reducesmanufacturing time and associated costs. Other embodiments, however, caninclude a manufacturing process wherein PU material may be injectionmolded onto various portions of the neoprene sock in more than one step.

If the boot assembly 10 being manufactured is the full-height,over-the-calf boot, the top edge of the upper 12 is finished, such as bybinding stitching the top edge, after the boot assembly is removed fromthe mold assembly 62. A foot bed, insole, or other insert may bepositioned into the interior area of the boot assembly after the bootassembly is removed from the mold assembly 62. If the boot assembly 10being manufactured is a shorter model, the upper 12 can be cut along theselected convertible channel 52, such as the lower convertible channel54, the 7-inch convertible channel 56, the 12-inch convertible channel58, or another convertible channel. After the upper 12 has been cutalong the selected convertible channel 52 to the desired height, the topedge of the upper's remaining portion is finished to complete theshorter, waterproof footwear assembly, such as the 4.5-inch “camp muc”shoe, the 7-inch boot, or the 12-inch boot. The upper portion of theneoprene sock 24 and any of the associated PU layer cut from the upperis manufacturing waste that can be recycled or thrown away.

In another embodiment, the boot assembly 10 made on the mold assembly 62can include inserts between the neoprene sock 24 and a portion of theinjection molded layer. For example, a shank can be positioned under thebottom of the neoprene sock as discussed above. Another embodiment caninclude a protective toe cap (i.e., a safety toe) that fits over the toeof the neoprene sock and is essentially encapsulated in the layer ofinjection molded material. Other embodiments can include otherprotective features such as a metatarsal guard, a puncture proof layerunder foot, a snake guard layer associated with some or all of theupper, and/or other protective features.

From the foregoing, it will be appreciated that specific embodiments ofthe invention have been described herein for purposes of illustration,but that various modifications may be made without deviating from theinvention. Additionally, aspects of the invention described in thecontext of particular embodiments or examples may be combined oreliminated in other embodiments. Although advantages associated withcertain embodiments of the invention have been described in the contextof those embodiments, other embodiments may also exhibit suchadvantages. Additionally, not all embodiments need necessarily exhibitsuch advantages to fall within the scope of the invention. Accordingly,the invention is not limited except as by the appended claims.

1. A footwear assembly, comprising: an outsole; and an upper connectedto the outsole, the upper comprising a sock layer having a leg portionhaving a front shin portion, side wall portions and a rear calf-sideportion; and a foot portion integrally connected to the leg portion andhaving a vamp portion; and a unitary outer injection molded layer moldeddirectly onto at least a portion of the sock layer, wherein the unitaryouter injection molded layer comprises a first injection molded regionthat encases the foot portion of the sock layer; and a second injectionmolded region on the shin portion of the leg portion of the sock layer,wherein the sidewall portions and calf-side portion of the sock layerremain exposed and substantially uncovered by the second injectionmolded layer, and wherein the second injection molded layer includes ashin guard having a necked down area and a shin area that is wider thanthe necked down area, the necked down area interconnecting the shin areaand the vamp portion. 2.-27. (canceled)